[ANNOUNCE] Apache HBase 2.0.0-alpha-3 is now available for download

[stack <st...@apache.org>]

The HBase team is happy to announce the immediate availability of Apache
HBase
2.0.0-alpha-3.

Apache HBase is an open-source, distributed, versioned, non-relational
database. Apache HBase gives you low latency random access to billions of
rows with millions of columns atop non-specialized hardware. To learn more
about HBase, see https://hbase.apache.org/.

hbase-2.0.0-alpha-3 is a rough cut ('alpha'), not-for-production preview of
what hbase-2.0.0 will look like. It is meant for devs and downstreamers to
test drive and flag us early if we messed up anything ahead of our rolling
GAs.

hbase-2.0.0-alpha-3 is our third alpha release on our march toward an
hbase-2.0.0. It includes all that was in previous alphas (new assignment
manager, offheap read/write path, in-memory compactions, etc.), but had a
focus on polishing our public API: old API that had been deprecated since
hbase-1.0.0 or before was purged and new API was added with sympathetic
deprecation of the previous. Along the Admin plane, incompatible changes
were unavoidable; you will not be able to administer a hbase2 cluster
using an hbase1 client (see dev-list "[DISCUSS] hbase-2.0.0 compatibility
expectations" thread for discussion and see [1] for current list of
Incompatibles).

What is here will be our public API for 2.0.0 unless we get pushback from
our gracious downstreamers.

Alpha-3 does not have the final version of our Coprocessor API. Finishing
the Coprocessor API for hbase-2.0.0 is the topic of our last planned alpha,
2.0.0-alpha-4. The Coprocessor API changes pretty radically in hbase-2.0.0
(though Coprocessor Endpoints will continue to work across an upgrade). See
[2] for why and why it was unavoidable. Input now from Coprocessor API users
before alpha-4 would be especially effective.

The list of features addressed in 2.0.0 so far can be found here [3]. There
are about 2700+. The list of ~500 fixes in 2.0.0 exclusively can be found
here [4].

We've updated our overview doc. on the state of 2.0.0 [6] but JIRA 2.0.0
label [5] has undergone extensive weeding and presents a fairly good
picture on what is yet to do before we 2.0.0. Check it out.

Please take it for a spin and let us know if there is anything you would
have us change or anything you see missing by mailing dev@hbase.apache.org
or by filing issues at https://issues.apache.org/jira/projects/HBASE/summary

We are planning one more alpha release before we move to beta (the above
mentioned alpha-4). Now is the time to catch the egregious and flag the
incompatibilities while we have time to bend. Once we move to beta, APIs
and feature-set will be fixed.

Download through an ASF mirror near you:

 https://www.apache.org/dyn/closer.lua/hbase/2.0.0-alpha-3

Checksums can be found here:

 https://www.apache.org/dist/hbase/2.0.0-alpha-3/hbase-2.0.
0-alpha3-bin.tar.gz.md5
 https://www.apache.org/dist/hbase/2.0.0-alpha-3/hbase-2.0.
0-alpha3-src.tar.gz.md5

Project member signature keys can be found at

    https://www.apache.org/dist/hbase/KEYS

PGP signatures are here:

 https://www.apache.org/dist/hbase/2.0.0-alpha-3/hbase-2.0.
0-alpha3-src.tar.gz.asc
 https://www.apache.org/dist/hbase/2.0.0-alpha-3/hbase-2.0.
0-alpha3-bin.tar.gz.asc

For instructions on verifying ASF release downloads, please see

    https://www.apache.org/dyn/closer.cgi#verify

Known issues are:

+ The LoadTestTool does not work (HBASE-18832).
+ MapReduce may fail for you (HBASE-18803 Mapreduce job get failed caused by
NoClassDefFoundError: org/apache/commons/lang3/ArrayUtils.)

Question, comments, and problems are always welcome at:
dev@hbase.apache.org.

Yours,
The HBase Dev Team

1. Current list of Incompatibles: https://docs.google.com/document/d/
1WCsVlnHjJeKUcl7wHwqb4z9iEu_ktczrlKHK8N4SZzs/edit#heading=h.723jjn18p2jr
2. Why CPs are Incompatible: https://docs.google.com/document/d/
1WCsVlnHjJeKUcl7wHwqb4z9iEu_ktczrlKHK8N4SZzs/edit#heading=h.9k7mjbauv0wj
3. goo.gl/Gcrp4f
4. goo.gl/xHE7fF
5. https://issues.apache.org/jira/projects/HBASE/versions/12327188
6. https://docs.google.com/document/d/1WCsVlnHjJeKUcl7wHwqb4z9iEu_
ktczrlKHK8N4SZzs/